You need to have the latest version of Pocket / Evernote app installed, as from Yosemite, El Capitan it provides a sharing extension, which is recommended to use by Apple.
Download Pocket from the Mac App Store
Download Evernote from the Mac App Store

Pocket / Evernote needs to be enabled at Newsflow / Preferences / Sharing and please make sure that the sharing is also enabled at System Preferences / Extensions / Share Menu list.

In case if you still don't see the sharing among your sharing options, please disable it at Share Menu list, restart your Mac and re-enable it.
Category: News, Feedly, Feedbin, RSS
Compatibility: MAC OS X Yosemite, El Capitan
Newsflow: News Reader for Mac OS X (Yosemite, El Capitan)

Newsflow brings news from all of your favourite websites right to your desktop. Enjoy your articles in a fast, fluent and highly customizable news reader.